Detection of the Oxidation Area by Spectrophotometry: Regional and Temporal Changes in Anodic Oxidation on Titanium in Bipolar Electrochemistry

Abstract

This study investigated the temporal change in the oxidation area on a titanium (Ti) bipolar electrode (BPE) subjected to bipolar anodization in a direct current (DC) electric field using a spectrophotometer. The rectangular Ti sheet used as a BPE was horizontally positioned at the center of a cell. After the DC bipolar anodization, the oxidized area was detected nondestructively and visually using a specific interference color that depends on the thickness of the barrier-type oxide film formed on the Ti BPE. The change in the L*a*b* color space corresponding to each interference color revealed that the oxidation area increased along the longitudinal axis of the BPE with the increasing electrolysis time by reflecting the change in the potential distributions on the BPE. As visually demonstrated, the area where the anodic reaction proceeded reached saturation at 90% of the BPE surface area.